Gas impervious diaphragms



Sept. l2, 1967 T A S11 CLAN; ET AL 3,340,734

GAS IMPERVIOUS DIAPHRAGMS Filed Jan. 26, 1965 2 Sheets-Shedl l @Mlm 67 TTOIQNEYS T. A. sT. CLAIR ET AL 3,340,734

GAS IMPERVIOUS DIAPHRAGMS Sept. 12, 1967 Filed Jan. 2e, 1965 2 Sheets-Sheet United States Patent O 3,340,734 GAS IMPERVIOUS DIAPHRAGMS Theodore A. St. Clair, Fairfield, and Ernest L. Greenhill, Milford, Conn., assignors to Textron Inc., Providence, RJ., a corporation of Rhode Island Filed Jan. 26, 1965, Ser. No. 428,184 6 Claims. (Cl. 73-279) ABSTRACT OF THE DISCLOSURE A stroke-through-center diaphragm for gas meters havling a rigid center plate and outer retaining flange concentric with the center plate and a trough-shaped annular member of impervious exible material extending between the center plate and retaining flange, said annular member at full outstroke having a smooth outer peripheral surface and ribbed inner peripheral surface .and upon being moved through center to full inner position decreasing the smooth outer peripheral surface and increasing the inner peripheral surface with the ribs creasing the increased peripheral surface all for the purpose of relieving circumferential stress and facilitating the diaphragm stroke.

Heretofore, ditiiculties have been encountered in the form of localized areas of stress or wear in stroke-throughcenter diaphragms, particularly of the type for use in slow operating gas meters, where it is essential that the diaphragms produce a long stroke for imparting the great- .est possible displacement per revolution of the meter, such wear being particularly aggravated in diaphragms having a synthetic diaphragm member, since the material of the diaphragm will not respond to multidirectional movement, as required in stroking. It has been found that in such diaphragms, the slightest overstroking or even long continuous use will tend to produce crows feet or similar areas of stress that eventually cause the diaphragm to fail.

It is an important object of the present invention, therefore, to provide a diaphragm of the stroke-through-center type, which is capable of full stroke operation and extensive and continuous use without developing points of stress or wear.

According to the invention, this is accomplished by providing the flexible portion of the diaphragm with means for permitting the expansion or contraction thereof during the stroking of the diaphragm, whereby circumferential stress relief of the material of the diaphragm is provided. More specifically, the diaphragm, which is normally movable from full outstroke position through midstroke position to full instroke position, is formed to the shape it will assume in one extreme of the stroking operation and is provided with means for progressively reshaping it as it is moved to its opposite extreme position, such reshaping enabling the flexible portion of the diaphragm to expand or contract, .as required, to avoid localized stress and eliminate wear.

In the preferred form of the invention, the strokethrough-center diaphragm includes, in addition to the convetnional center plate and outer retaining ange, a i.

flexible impervious trough-shaped annular diaphragm member having inner and outer peripheral surfaces, the

inner peripheral surface being shaped, in the full outstroke position of the diaphragm, to provide a plurality of radially extending ribs which define creases or valleys 'i in the inner surface and are adapted as the diaphragm is stroked, to full instroke position, to progressively pleat the material of the diaphragm member to extend the creases thereacross, whereby the creases may circumferentially contract for providing circumferential stress 34,340,734 Patented Sept. 12, 1967 relief for the diaphragm and to facilitate the diaphragm stroke.

It is also an object of the present invention to provide a method of making stroke-through-center diaphragms, wherein the molding step thereof comprises the improvement of molding the flexible ,annular trough-shaped diaphragm member in substantially its full outstroke position, thereby shaping such member to provide means which progressively pleat the member as it is stroked through midstroke position to full instroke position, thus enabling the diaphragm to expand or contract for providing circumferential stress relief.

Other objects and advantages of the invention will be apparent from the. specification and claims, when considered in connection with the attached sheet of drawings, illustrating one form of the invention, wherein like characters represent like parts .and in which:

FIGURE 1 is a plan view of a stroke-through-center diaphragm according to the invention, in its full outstroke position;

FIG. 2 is a fragmentary plan view of the diaphragm of FIG. 1 in midstroke position;

FIG. 3 is a fragmentary plan view of the diaphragm of FIG. 1 in full instroke position;

FIG. 4 is a fragmentary cross-sectional view of the diaphragm in full outstroke position, as shown in FIG. 1, taken in the direction of the .arrows 4 4;

FIG. 5 is a fragmentary cross-sectional view of the diaphragm in midstroke position, as shown in FIG. 2, taken in the direction of the arrows 5 5; `and FIG. 6 is a fragmentary cross-sectional View of the diaphragm in full instroke position, as shown in FIG. 3, taken in the direction of the arrows 6-6.

Referring now to the drawings for .a more detailed description of the invention, a stroke-through-center diaphragm 10 is shown, of the type which is adapted to be moved from full outstroke position (FIGS. 1 and 4) through midstroke position (FIGS. 2 ,and 5) to full instroke position (FIGS. 3 and 6) and vice versa for opera-ting a device, such las a gas meter or the like.

As illustrated, and as is conventional in devices of this type, the diaphragm 10 includes a substantially rigid center plate 11, a retaining flange 12 concentric with and spaced from the center plate `for mounting the diaphragm and a eXible gas impervious .annular member 13 extending between and connected to the center plate and ange.

The annular member 13, which flexes back and forth to enable the diaphragm to be stroked through its cycle of operation, as illustrated, is substantially trough-shaped in cross-section and is connected to the center plate 11 and retaining ange 12 closely adjacent its inner and outer peripheral edges 14 and 15, respectively. While 'such connection may be made directly to the edges, as shown in the connection of outer peripheral edge 15 with retaining flange 12, wherein the edge is crimped in a U-shaped inner circumferential rim 16 of the ange, in the illustrated and preferred form yof diaphragm construction, in order to assure that the diaphragm is gas impervious across its entire expanse, the annular member 13 has a central web 17 forming a unitary extension of the inner peripheral edge 14 and extending across the space defined by such edge. This web, which may be connected to the center plate in anylknown manner, is here shown clamped between the plate forming members 18 and 19 by a nut and bolt type fastener 20.

While stroke-through-center diaphragms of the type here described have been known and used in the art for a substantial period of time, it hasbeen found that such diaphragms, particularly when they are formed of ysynthetic materials, tend to wear Vin localized areas, as the 3 result of stress in such areas when they are subjected to multidirectional movement; the material forming the flexible annular member is unable to respond to the multidirectional movement required in stroking through a full cycle and is subjected to circumferential stress which eventually causes it to wear and breakdown in localized areas.

The present invention overcomes this problem and eliminates localized wear of the .diaphragm by initially vforming the flexible annular member thereof in lone extreme position of the stroking cycle and shaping it to provide means Which progressively redistribute the material of the member as the diaphragm is stroked to the opposite extreme position of the cycle.

According to the invention, the prior method of making stroke-through-center diaphragms, which includes molding the flexible annular member, preferably of synthetic elastomeric material, and then connecting it to a center plate and outer retaining flange to extend therebetween, is improved by molding the annular member in its full outstroke position and shaping it so that radially extending ribs are formed in at least a portion of its surface, the ribs defining radially extending creases therebetween and functioning, as the diaphragm is stroked to full instroke position, to positively pleat the material for extending the creases, thus enabling the creases to circumferentially contract for eliminating circumferential stress.

Referring again to the drawings, and FIGS. 1 and 4 in particular, the diaphragm is shown in its full outstroke position, the annular member 13 thereof being in the position it wasl initially molded. As will be seen, the annular member has a substantially smooth radially linear outer peripheral surface 21 generated by the movement of a line in the plane of the radius of the member around the axis of the member. While the surface 21 may take many forms, in the illustrated and preferred form of the invention it is frustro-conical and is generated by the movement around the axis of the member of an inwardly inclined line in the plane of the radius of the member.

The inner peripheral surface 22 of annular member 13 is shaped to lprovide a plurality of radially extending ribs 23, which define therebetween creases or valleys 24, the ribs and creases extending substantially across the inner peripheral surface and ending adjacent or in the outer peripheral surface.

Referring now to all Vof the figures, it will be seen that when the diaphragm 10` is stroked from its full outstroke position (FIGS. 1 and 4) through midstroke position (FIGS. 2 and`5 to full instroke position (FIGS. 3 and 6), the outer peripheral surface 21 progressively decreases in radial dimension or width as the inner peripheral surface increases in such dimension. Simultaneously, the ribs 23 progressively pleat the material of the increasing inner peripheral surface to extend the creases 24 thereacross, thus enabling the creases to circumferentially contract, whereby circumferential stress in the annular member is relieved and the stroking operation is facilitated. It will be understood by those conversant with the art that stroking of the diaphragm in the reverse direction will merely reverse the aforesaid sequence, thus permitting theV material of the annular member to progressively redistribute itself and returnl to its original condition.

It should here be noted that, as used herein and in the appended claims, the term radially linear -rneans linear in a direction in the plane of the radius of the annular member and radial dimension similarly refers to a dimension along a line in the plane of the radius of such member.

Thus, among others, the several objects and advantages of the invention as aforenoted are achieved. Obviously numerous changes in the structure may be resorted to without departing from the spirit of the invention as defined by the claims.

We claim:

1. A stroke-through-center diaphragm for gas meters which is movable from full outstroke position through midstroke position to full instroke position, said diaphragm comprising a substantially rigid center plate, an outer retaining flange concentric with and substantially parallel to said center plate, and a flexible impervious troughshaped annular member connected to and extending between said center plate and flange, said annular member in the full outstroke position of said diaphragm having a substantially smooth outer peripheral surface concentric with the axis of said annular member and having an inner peripheral surface shaped to provide a plurality of spaced radial ribs in said inner peripheral surface defining radial creases therebetween, Isaid creases and ribs extending at least to said outer peripheral surface, said outer peripheral surface decreasing in width and said inner peripheral surface increasing in width as said diaphragm is moved from full outstroke position through midstroke position to full instroke position, said shaped ribs pleating said increased inner peripheral surface to extend said creases thereacross, whereby said creases circumferentially contract for providing circumferential stress relief and to facilitate the diaphragm stroke.

2. A stroke-through-center diaphragm for gas meters which is movable from full outstroke position through midstroke position to full instroke position, said diaphragm comprising a substantially rigid center plate, an outer retaining flange concentric with and substantially parallel to said center plate, and a flexible impervious trough-shaped annular member connected to and extending between said center plate and flange, said annular member in the full outstroke position of said diaphragm having a substantially radially linear outer peripheral surface inclined toward the axis of said member and having an inner peripheral surface shaped to provide a plurality of spaced radial reinforcing -ribs in said inner peripheral surface defining radial creases therebetween, said creases and ribs extending at least to said outer peripheral surface, said outer peripheral surface decreasing in radial dimension and said inner peripheral surface increasing in -radial dimension as said diaphragm is moved from full outstroke position through midstroke position to full instroke position, said shaped reinforcing ribs pleating said increased inner peripheral surface to extend said creases thereacross, whereby said creases circumferentially contract for providing circumferential stress relief and to facilitate the diaphragm stroke.

3. A stroke-through-center diaphragm for gas meters which is movable from full outstroke position through midstroke position to full instroke position, said diaphragm comprising a substantially rigid center plate, anouter retaining flange concentric with and substantially parallel to said center plate, and a flexible impervious unitary diaphragm member including a trough-shaped annular portion having inner and outer peripheral surfaces and aweby extending across the area defined by said inner peripheral surface, said web being reinforced by said center plate, said annular portion being connected to and extending between said center plate and flange, said outer peripheral surface of said annular portion in the full outstroke position of said diaphragm being substantially radially linear and inclined toward the axis of said annular portion and said inner peripheral surface of said annular portion being shaped to provide a plurality of spaced radial ribs defining radial creases therebetween, said creases and ribs extending at least to said outer peripheral surface, said outer peripheral surface decreasing in radial dimension and said inner peripheral surface increasing in radial dimension as said diaphragm is moved from full outstroke position through midstroke postion to full instroke position, said shaped ribs pleating said increased inner peripheral surface to extend said creases thereacross, whereby said creases circumferentially contract for providing circumferential stress relief and to facilitate the diaphragm stroke.

4. A stroke-through-center diaphragm ifor gas meters which is movable from full outstroke position through midstroke position to full instroke position, said diaphragm comprising a substantially rigid center plate, an outer retaining flange concentric with and substantially parallel to said center plate, and a flexible impervious trough-shaped annular member connected to and extend ing between said center plate and iiange, said annular member in the full outstroke position of said diaphragm having an outer peripheral surface generated by the -movement of a line in the plane of the radius of said member around the center of said member and having an inner perip-heral surface shaped to provide a plurality of spaced radial ribs in said inner peripheral surface defining radial creases therebetween, said creases and ribs extending at least to said outer peripheral surface, said outer peripheral surface decreasing in Width and said inner peripherall surface increasing in Width as said diaphragm is moved from lfull outstroke position through midstroke position to full instroke position, said ribs pleating said increased inner periph-eral surface to extend said creases thereacross, whereby said creases circumferentially contract for providing circumferential stress relief and to facilitate the diaphragm stroke.

5. A stroke-through-center diaphragm for gas meters which is movable from full outstroke position through midstroke position to full instroke position, said diaphragm comprising a substantially rigid center plate, an outer retaining flange concentric with and substantially parallel to said center plate, and a flexible impervious trough-shaped annular member connected to and extending between said `center plate and flange, said annular member in the full outstroke position of said -diaphragm having an outer peripheral surface generated by the movement of an angularly disposed line in the plane of the radius of said member around the center of said member and having an inner peripheral surface contiguous with said outer surface and shaped to provide a plurality of spaced radial stiffening ribs in said inner peripheral surface defining radial creases therebetween, said creases and ribs extending at least to said outer peripheral surface, said outer peripheral surface decreasing in width and said inner surface increasing in Width as said diaphragm is moved from full outstroke position through midstroke position to full instroke position, said stiffening Iribs pleating said increased inner surface to extend said creases thereacross, whereby said creases contract for providing circumferential stress relief and to facilitate the diaphragm stroke.

6. A stroke-through-center diaphragm for gas meters which is movable from `full outstroke position through midstroke position to full instr-oke position, said diaphragm comprising a substantially rigid center plate, an outer retaining flange concentric with and substtantially parallel to said center plate, and a flexible impervious trough-shaped annular member connected to and extending between said center plate and flange, said annular member in the full outstroke position of said diaphragm having an outer peripheral substantially frusto-conical surface generated by the movement of an inwardly angularly disposed line in the plane of the radius of said member around the center of said member and having an inner peripheral surface contiguous with said outer surface and shaped to provide a plurality of formed spaced radial stiffening ribs in said inner peripheral surface defining radial creases therebetween, said creases and ribs extending substantially across the width of said inner peripheral surface and at least to said outer peripheral surface, said outer peripheral surface decreasing in Width and said inner surface increasing in Width as said diaphragm is moved from full outstroke position through midstroke position to full instroke position, said ribs progressively pleating said increased inner peripheral surface to extend said creases thereacross, whereby said creases contract for providing circumferential stress relief and to facilitate the diaphragm stroke.

References Cited UNITED STATES PATENTS 1,793,621 2/1931 Kelley 92-104 2,632,475 3/1953 Elo 92-104 X 2,874,569 2/ 1959 Gray 73-279 JAMES J. GILL, Primary Examiner.

RICHARD C. QUEISSER, Examiner.

E. D. GILHOOLY, Assistant Examiner. 

1. A STROKE-THROUGH-CENTER DIAPHRGM FOR GAS METERS WHICH IS MOVABLE FROM FULL OUTSTROKE POSITION THROUGH MIDSTROKE POSITION TO FULL INSTROKE POSITION, SAID DIAPHRAGM COMPRISING A SUBSTANTIALLY RIGID CENTER PLATE, AN OUTER RETAINING FLANGE CONCENTRIC WITH AND SUBSTANTIALLY PARALLEL TO SAID CENTER PLATE, AND A FLEXIBLE IMPERVIOUS TROUGHSHAPED ANNULAR MEMBER CONNECTED TO AND EXTENDING BETWEEN SAID CENTER PLATE AND FLANGE, SAID ANNULAR MEMBER IN THE FULL OUTSTROKE POSITION OF SAID DIAPHRAGM HAVING A SUBSTANTIALLY SMOOTH OUTER PERIPHERAL SURFACE CONCENTRIC WITH THE AXIS OF SAID ANNULAR MEMBER AND HAVING AN INNER PERIPHERAL SURFACE SHAPED TO PROVIDE A PLURALITY OF SPACED RADIAL RIBS IN SAID INNER PERIPHERAL SURFACE DEFINING RADIAL CREASES THEREBETWEEN, SAID CREASES AND RIBS EXTENDING AT LEAST TO SAID OUTER PERIPHERAL SURFACE, SAID OUTER PERIPHERAL SURFACE DECREASING IN WIDTH AND SAID INNER PERIPHERAL SUR- 